Although providing support to underachievers has always been an important domain of activities of school counselors in school, there are almost no studies in our country that focus on the opinion of school counselors on the problem of underachievement. The aim of our research was to get acquainted with the meanings that school counselors ascribe to underachievement. The points of our interest were how school counselors define this phenomenon, how they describe an underachiever and what their experiences in working with these students are. The research sample was convenient and included 34 school counselors from 24 secondary schools in Serbia. We used a semi-structured interview, and qualitative thematic analysis was performed on the collected material. Research findings indicate that the majority of school counselors define underachievement as the lack of ability or readiness of individuals to respond to the demands set by school. When describing an underachiever a number of school counselors speak only about his/her behaviour, while a small number also mention the mechanisms underlying such behaviour. When it comes to their experience in working with underachievers, a considerable number of school counselors pointed to the complexity and delicacy of their own role in the process of selection of adequate support strategies. The obtained findings, among other things, suggest that it is necessary that school counselors re-examine those personal beliefs about underachievement which can be a serious impediment to solving this problem. [Projekat Ministarstva nauke Republike Srbije, br. 47008: Unapređivanje kvaliteta i dostupnosti obrazovanja u procesima modernizacije Srbije i br. 179034: Od podsticanja inicijative, saradnje i stvaralaštva u obrazovanju do novih uloga i identiteta u društvu]